论文标题
同步误差的卷积代码的顺序解码
Sequential Decoding of Convolutional Codes for Synchronization Errors
论文作者
论文摘要
连续解码通常应用于替代通道，是Viterbi解码的替代替代方案，其存储成本大大降低。在这项工作中，描述和分析了容易插入，删除和替换误差的通道上的卷积代码的顺序解码器。我们的解码器通过Davey和Mackay提出的新的频道状态变量（称为漂移状态）扩展了代码格子。得出了该格子上的一个合适的解码度量，以进行顺序解码，从而推广原始的Fano度量。还扩展了解码器，以促进由单个传输序列产生的多个接收序列的同时解码。在低噪声环境下，与Viterbi的算法相比，我们的解码方法通过几个数量级降低了解码的复杂性，尽管以较高的位错误率。还提出了一种确定计算截止率的分析方法。该分析得到了对位错误率和计算复杂性的数值评估，这些评估与最佳Viterbi解码相比。
Sequential decoding, commonly applied to substitution channels, is a sub-optimal alternative to Viterbi decoding with significantly reduced memory costs. In this work, a sequential decoder for convolutional codes over channels that are prone to insertion, deletion, and substitution errors, is described and analyzed. Our decoder expands the code trellis by a new channel-state variable, called drift state, as proposed by Davey and MacKay. A suitable decoding metric on that trellis for sequential decoding is derived, generalizing the original Fano metric. The decoder is also extended to facilitate the simultaneous decoding of multiple received sequences that arise from a single transmitted sequence. Under low-noise environments, our decoding approach reduces the decoding complexity by a couple orders of magnitude in comparison to Viterbi's algorithm, albeit at slightly higher bit error rates. An analytical method to determine the computational cutoff rate is also suggested. This analysis is supported with numerical evaluations of bit error rates and computational complexity, which are compared with respect to optimal Viterbi decoding.
